A known accelerator apparatus controls an acceleration state of a vehicle according to the amount of depression of an accelerator pedal, which is depressed by a foot of a driver of the vehicle. In this accelerator apparatus, a rotational angle of a rotatable shaft, which corresponds to a rotational angle of a pedal arm having the accelerator pedal connected thereto, is sensed. In the vehicle, an opening degree of a throttle valve, which adjusts a quantity of intake air drawn into an internal combustion engine of the vehicle, is determined based on the sensed rotational angle.
A return mechanism and a hysteresis mechanism are received in an interior space of a support member of the accelerator apparatus. The return mechanism urges the rotatable shaft toward an accelerator closing direction. The hysteresis mechanism makes a pedal force, which is applied to an accelerator pedal at the time of depressing the accelerator pedal, to be larger than a pedal force, which is applied to the accelerator pedal at the time of releasing the accelerator pedal. The return mechanism includes a return spring that urges a pedal boss portion, which is fixed to an outer wall of the rotatable shaft and is rotatable integrally with the rotatable shaft, in the accelerator closing direction. Furthermore, the hysteresis mechanism includes a hysteresis spring that urges a hysteresis boss portion, which is engaged with the pedal boss portion and is rotatably placed on a radially outer side of the rotatable shaft, in the accelerator closing direction. For example, JP2013-147211A (corresponding to US2013/0186228A1) discloses an accelerator apparatus that has a return spring and a hysteresis spring, which are received in an inside of a support member such that the return spring and the hysteresis spring are arranged side-by-side and extend in a top-to-bottom direction.
In the accelerator apparatus of JP2013-147211A (corresponding to US2013/0186228A1), one end of the return spring and one end of the hysteresis spring contact an inner wall of the support member. In the inner wall of the support member, a guide, which is in a form of a projection, is formed between a first contact surface, which contacts one end of the return spring, and a second contact surface, which contacts one end of the hysteresis spring. The guide is formed to be relatively large to implement a sufficient strength for limiting positional deviation of the return spring and a positional deviation of the hysteresis spring. Thus, in the accelerator apparatus of JP2013-147211A (corresponding to US2013/0186228A1), which has the first contact surface, the guide in the form of the projection, and the second contact surface that are arranged one after another in the top-to-bottom direction, a size of the support member in the top-to-bottom direction becomes disadvantageously large.